Sealing cover with an anti-unscrew safety device

ABSTRACT

The invention relates to a sealing cover ( 11 ) for openings radiators in vehicles. Said cover comprises an outer part ( 10 ) which is provided with a sealing element ( 13 ) which can be connected to a container pipe, and a grip element ( 12 ) which is rotationally maintained in relation thereto, and a rotational-prevention device which comprises a coupling insert ( 80 ) which is rotationally fixed with the handling element ( 12 ) and which can be axially engaged or disengaged in the sealing element ( 13 ) for detachably rotationally fixing the sealing and the grip element. The aim of the invention is to produce a sealing cover which can only be unscrewed by a specialist and not an amateur when the anti-unscrew safety device is activated. As a result, an axial displacement of the grip element ( 12 ) is possible in at least a central area in relation to the sealing element ( 13 ) when the coupling insert ( 80 ) is disengaged and the grip element ( 13 ) is simultaneously rotated, a rotating a sealing connection ( 95 ) in an axially sealing and radially active manner occurring on a peripheral area.

[0001] The present invention relates to a sealing cover, or cap, for openings of containers, in particular motor vehicle radiators, as generically defined by the preamble to claim 1.

[0002] In such sealing caps, the particular advantage is that the sealing cap cannot be unscrewed from the radiator if an overpressure prevails in the cooling system because the coolant has become heated. This protects the user of motor vehicles from radiators that boil over because of hot coolant. Since the sealing cap can be unscrewed only whenever the radiator is essentially pressureless, there is a problem in that this is also true for the shop or automotive repair or servicing facility. In other words, in the shop, either the vehicle has to be allowed to stand for some time, or the radiator has to be artificially cooled down in some way. This is time-consuming and inconvenient.

[0003] The object of the present invention is therefore to create a sealing cap of the type defined above that is prepared in such a way that with the anti-unscrew safety device connected, it cannot be unscrewed by the lay person, but can be unscrewed intentionally by the mechanic at the shop or repair facility.

[0004] To attain this object, the characteristics recited in claim 1 are provided in a sealing cap of the type defined above.

[0005] By the provisions of the invention, because of the combination of motion preconditions or motion sequences, it is possible for a professional mechanic to overcome the rotation prevention. However, this special position for circumventing the anti-unscrew safety device cannot be reached unintentionally by the lay person.

[0006] An advantageous structural feature in this respect is attained by the characteristics of claim 2. The result is a direct connection, in a manner fixed against relative rotation, between the grip element and the closure element. To make it possible to circumvent the rotation prevention more intentionally, or to make this circumvention more difficult, the characteristics of claim 3 are provided. This means that only if axial pressure is exerted intentionally on the grip element, and if this axial pressure is sufficiently well maintained, is an opening motion of the closure element possible.

[0007] The axial mobility of the grip element relative to the closure element can be made possible for instance by an elasticity of the central area of the grip element, compared to its circumferential edge. Advantageously, however, the characteristics of claim 4 are provided for this purpose, which for an overall rigid grip element offer the possibility of an axial motion relative to the closure element.

[0008] To strengthen the positive or nonpositive engagement upon the opening motion that overcomes the closure protection, the characteristics of claim 5 are provided. In other words, the rotationally fixed connection is based not only on the direct connection of the grip element and the closure element, but is also enhanced and assured by the indirect rotationally fixed connection via the coupling insert.

[0009] Expediently, the characteristics of one or more of claims 6-8 are provided in this respect. A further advantageous embodiment of the coupling insert, whose rotation prevention as a result possible with direct dependency on and in chronological succession with the conditions prevailing in the container interior, is obtained from the characteristics of claim 9. According to the characteristics of claim 10, the coupling insert is triggered by the valve body directly.

[0010] Further advantageous structural features of the coupling insert will become apparent from the characteristics of one or more of claims 11-13.

[0011] Further details of the invention can be learned from the ensuing description, in which the invention is described in further detail in terms of the exemplary embodiment shown in the drawing. Shown are:

[0012]FIG. 1, in a schematic perspective view, half in section, a sealing cap for a motor vehicle radiator, with an overpressure/negative-pressure valve assembly and with a rotation preventer, each in the closed or nonactivated outset position, in a preferred exemplary embodiment of the present invention;

[0013]FIG. 2, a view corresponding to FIG. 1, but during the buildup of an overpressure in the container interior, in an overpressure position of the valve assembly and with the rotation preventer activated;

[0014]FIG. 3, a view corresponding to FIG. 2, but with a rotation preventer deactivated by intentional action; and

[0015]FIG. 4, in an enlarged view, an axial section through the auxiliary rotationally fixed connection of FIG. 3.

[0016] The sealing cap 11, for instance for a radiator, shown in the drawing in a preferred exemplary embodiment, has an outer cap part 10, provided with a grip element or actuating handle 12, on whose closure element 13, embodied here as a screw-on element, an inner cap part 14 with a negative-pressure/overpressure valve assembly 15 is held such that it is suspended and is relatively rotatable. In the position for use, the sealing cap 11 is fixed, for instance screwed, to a radiator stub, not shown. The inner cap part 14 protrudes into the radiator stub in the direction of the radiator interior. An O-ring 16 seals off the inner cap part 14 from the radiator stub wall. In the outer cap part 10, which is split into two parts, the caplike actuating handle 12 is fixed on the screw-on element 13 such that it is movable axially by a few millimeters but is rotatable over 360° in the circumferential direction. At normal pressure in the radiator interior, this rotatability is blocked by an axially movable coupling insert 80 for screwing the sealing cap 11 on and unscrewing it.

[0017] The overpressure part of the valve assembly 15 is embodied in two stages and serves to prevent the radiator from boiling dry in a first overpressure stage, and in a second overpressure stage, assurance against damage to the radiator system from excessive overpressure is guaranteed. The overpressure part of the valve assembly 15 has a first valve body 17, a second valve body 18, and a third valve body 19, all in the interior of the inner cap part 14. The first valve body 17 is disposed above the second valve body 18, in the direction of the outside of the cap, while the third valve body 19 is received coaxially inside the second valve body 18.

[0018] The first valve body 17, embodied in two parts, has a radially inner valve body part 65, approximately in the form of a valve plate, and a radially outer valve body part 66; these parts overlap peripherally, and the radially inner valve body part is seated on the radially outer valve body part. On the side of the two valve body parts 65, 66 toward the radiator interior, an annular diaphragm seal 21 provided with axially inward-oriented sealing faces, is mounted. The radially inner, stepped valve body part 65 of the first valve body 17 is acted upon, from a side remote from the radiator interior by a closing compression spring 22, which is braced with its end remote from the first valve body 17 on a spring plate 23 that in turn is braced on the inner cap part 14. By means of the closing compression spring 22, the radially outer valve body part 66 of the first valve body 17 is prestressed in the direction of the radiator interior. Via the radially outer, flat sealing edge 68 of the diaphragm seal 21, the radially outer valve body part 66 is seated on a first annular sealing seat 24 of the second valve body 18. The radially inner valve body part 65 of the first valve body 17 has a central recess 37, whose annular boundary edge is gripped all the way around by the inner part of the diaphragm seal 21. This radially inner U-shaped sealing edge 67 of the diaphragm seal 21 forms a sealing face, toward the container interior, for a negative-pressure valve 57. On the outer edge, the radially inner valve body part 65 on the inner edge of the radially outer valve body part 66 of the first valve body 17. The radially inner valve body part 65 is guided axially inside the spring plate 23 and is joined to it, for instance via a set of teeth, in a manner fixed against relative rotation.

[0019] Near its radially outer edge, the radially inner valve body 65 has a stepped annular face 69, on which a cylindrical part 82, bearing a shim 85, of the coupling insert 80 that is rotatable relative to the valve body 65 is seated under the influence of a compression spring 81, which is braced on the inside of the grip element 12 of the outer cap part 13 on the shim 85. Both the shim 85 and the inside of the grip element 12 are provided with a cylindrical guide attachment for the compression spring 81. Remote from the lower annular face end that is seated on the valve body 65, and near its upper face end, the cylindrical attachment 82 of the coupling insert 80 has a first set of teeth 86, on its outer circumference, of a rotationally fixed connection 90 between the grip element 12 and the closure element 13. A second set of teeth 87 of the rotationally fixed connection 90 is provided on the inside circumference, on a cylindrical attachment 91 that protrudes axially from the inside of the grip element 12, and a third set of teeth 88 of the rotationally fixed connection 90 is provided on the inside circumference of a radial annular edge 92, which is in one piece with the closure element 13. As can be seen from FIG. 1, the axial length of the first set of teeth 86 of the rotationally fixed connection 90 on the coupling insert 80 is such that, in the outset position shown in FIG. 1, there is a rotationally fixed connection of the first set of teeth 86 on the coupling insert 80 both with the second set of teeth 87 on the grip element 12 and with the third set of teeth 88 on the closure element 13. In other words, in this outset or normal-pressure position, via the coupling insert 80, by meshing of the axially oriented sets of teeth, a rotationally fixed connection exists between the grip element 12 and the closure element 10 of the outer cap part 13, so that the sealing cap 11 can be screwed onto and unscrewed from the filler stub, not shown, of a container.

[0020] The grip element 12 covers the closure element 13 in hoodlike fashion; near the lower edge the grip element 12 has a circumferential groove 71 extending along the inside, and the closure element 13 has a circumferential lug 72 on the outside, which engages the circumferential groove 71 and allows a circumferential rotation of the grip element 12 relative to the closure element 13 when, as will be described hereinafter, the coupling insert 80 is suitably disengaged. The axial width of the circumferential groove 71 is greater than that of the circumferential lug 72, such that as can be seen from a comparison of FIGS. 1 and 3, the grip element 12 can be forced axially downward out of this position, that is, in the direction of the container pipe, relative to the closure element 13.

[0021] The grip element 12 is kept spaced apart from the closure element 13 by means of a wavelike spring ring 73. The axial motion of the grip element 12 that has just been described relative to the closure element 13 toward the container pipe extends counter to the action of the spring ring 73. A ring seal 74 is also disposed between the grip element 12 and the closure element 13; it prevents hot water or steam from passing out of the interior as the valve assembly 15 is opening. The spring ring 73 and the sealing ring 74 are disposed on the inside of the grip element 12 in an annular chamber 75, which is defined by the radially inner cylindrical attachment 91 and a radially outer cylindrical attachment 76 of the grip element 12. In the outset state shown in FIG. 1, both the free face end 93 of the radially inner cylindrical attachment 91 and the free face end 77 of the radially outer cylindrical attachment 76 are spaced apart from the top of the annular edge 92 of the closure element 13.

[0022] Between the grip element 12 and the closure element 13, for circumventing the disengaged rotationally fixed connection, an rotationally fixed connection 95 for emergency or servicing purposes is provided, which functions only whenever certain unique circumferential regions of the grip element 12 and the closure element 13 are made to coincide with one another and the grip element 12 is moved axially toward the closure element 13, counter to the action of the spring ring 73 and counter to the internal container pressure. For that purpose, on the free face end 77 of the radially outer cylindrical attachment 76 of the grip element 12, there is an axially protruding closure lug 78 at one circumferential point and a closure recess 97 at another circumferential point of the annular edge 92 of the closure element 13 and the lug and recess fit into one another. The closure lug 78 and the closure recess 97 engage one another only whenever the grip element 12 is moved by the axial length of the closure lug 78, which otherwise slides along the surface of the annular edge 92 of the closure element 13. The closure lug 78 and the closure recess 97 each have a respective oblique face 79 and 99 (FIG. 4) in the direction of the opening motion, whose angle is such that although a rotationally fixed connection is possible, this is true only whenever the closure lug 78 has plunged all the way into the closure recess 97 while maintaining the axial closure pressure.

[0023] The one-piece second valve body 18 has a hood part 26, which on its free face end is provided with the first sealing seat 24, and also has a concentric, hollow-cylindrical receptacle part 27 for the third valve body 19, which part points toward the radiator interior from the bottom of the hood part 26. A second ring seal in the form of an O-ring 31 is received in the bottom, in a circumferential groove on the outer circumference, and a second sealing seat 32 is associated with this O-ring and is formed by a collar edge on the inner cap part 14. In the lower region, the inner cap part 14 is provided with an axial opening 33. By means of the closing compression spring 22, the radially outer valve body part 66 of the first valve body 17 is pressed by the sealing edge 68 of the first ring seal 21 against the first sealing seat 24 of the second valve body, which in turn is pressed with its second ring seal 31 against the second sealing seat 32 on the inner cap part 14.

[0024] Between the underside of the first ring seal 21 of the first valve body 17 and the top of the second valve body 18, there is a cylindrical chamber 34, whose outer circumference is constant in the axial direction. Via a bore 36 in the bottom, the chamber 34 communicates centrally with a recess 38 in the second valve body 18. The recess 37 discharges at a conical region, disposed on the free end of the receptacle part 27, into the axial opening 33 of the inner cap part 14. Between the bore 36 and the recess 38, the second valve body 18 has a shoulder, which points toward the radiator interior and on which a third, flat ring seal 39 is retained.

[0025] The third valve body 19 is received axially movably in the recess 38 of the second valve body 18. It has a neck region of smaller diameter, which is movable in the bore 36 and inside the third ring seal 39, as well as a shoulder region, which forms a third sealing seat 43 in association with the third ring seal 39 on the second valve body 18, and also has a cylindrical belly region. A second compression spring 46 is provided inside the recess 38; it is braced on one end on the underside of the third ring seal 39 of the second valve body 18 and on the other on a shoulder of the third valve body 19. By means of the second compression spring 46, the third valve body 19 is prestressed in the direction of the radiator interior. Between the belly region of the third valve body 19 and the inner circumference of the recess 38 of the second valve body 18, there is an annular gap of very slight width, which, like the bore 36 and the chamber 34, is part of a first flow connection 50 between the inside of the cap and the outside of the cap. A second flow connection 51 leads past the outer circumference of the second valve body 18.

[0026] The opening that is closed, on the side toward the radiator interior, by the negative-pressure valve body 57 of the valve assembly 15 is located in the center of the radially inner valve body part 65 of the first valve body 17. The negative-pressure valve body 57, with its main portion, protrudes through the central opening and is acted upon by a third compression spring 59, which is braced on one end on a shoulder of the main part and on the other on a face, on the outside of the cap, of the radially inner valve body part 65. In this way, the negative-pressure valve body 57 is placed sealingly with its annular sealing seat 61 against the underside of the radially inner sealing edge 67 of the first ring seal 21 of the first valve body 17. The sealing seat 61 of the negative-pressure valve body 57 is located radially inside the first sealing seat 24 of the second valve body 18, while this first sealing seat is located radially outside the second sealing seat 32 of the inner cap part 14, and this second sealing seat is in turn located radially outside the third sealing seat 43 on the third valve body 19. All the sealing seats 24, 32, 43, 61 point axially outward, while all the sealing faces 21, 31, 39 point axially inward.

[0027] In the outset operating position shown in FIG. 1, in which a first limit value of the internal container pressure has not yet been exceeded, the first flow connection 50 is closed as a result of the sealing contact of the first valve body 17, with its first ring or diaphragm seal 21, on the first sealing seat 24 of the second valve body 18. In other words, in the chamber 34 and thus on the underside of the first ring seal 21 of the first valve body 17, the pressure prevailing in the container interior is present through the annular gap, in the form of the air cushion located above the liquid coolant. The second flow connection 51 along the outer circumference of the second valve body 18 is closed as a result of the sealing contact of the second seal 31 of the second valve body 18 with the second sealing seat 32 of the inner cap part 14.

[0028] If the internal container pressure increases to a certain amount that is above the normal or ambient pressure but is below a first limit value of the internal container pressure, then the anti-unscrew safety device of the sealing cap 11 is activated. As shown in FIG. 2, the radially inner valve body part 65 of the first valve body 17 is moved upward, while the second valve body 18 remains in its sealing position. Moreover, the radially outer valve body part 66 of the first valve body 17 remains in its position that provides sealing from the second valve body 18. The diaphragm ring seal 21 allows this relative motion between the radially inner valve body part 65 and the radially outer valve body part 66, because of its the meandering shape of this ring seal between its two sealing edges 67 and 68. With the motion of the radially inner valve body part 65 in the direction of the arrow A outward, the seated coupling insert 80 is moved counter to the action of the compression spring 81 and moves with its first set of teeth 86 away from the third set of teeth 88 on the closure element 13; the sets of teeth 86 and 88 become disengaged. This axial motion comes to an end whenever the radially inner valve body part 65, with its upper face end, strikes a stop 28 of the spring plate 23 (FIG. 2). A gap remains between the upper face end of the cylindrical part 82 and the inside of the grip element 12, so that the cylindrical part 82 remains easily rotatable in the valve body part 65. As a result of this disengagement motion of the coupling element 80 out of the closure element 13 of the outer cap part 10, the effect is that the grip element 12 rotates idly relative to the closure element 10, so that beyond a certain defined overpressure (in this case, 0.3 bar, for instance), unscrewing of the sealing cap 11 from the container fill stub is no longer possible. This rotation prevention is preserved even if the container pressure increases further.

[0029] If in this disengaged position of the coupling insert 80 the sealing cap 11 is nevertheless to be rendered unscrewable from the container stub by a professional entrusted with the task, then the second rotationally fixed connection 95 for servicing purposes is activated. This is done in such a way that with axial pressure in the direction of the arrow S on the grip element 12 in the direction of the closure element 13, the grip element 12 is rotated in one or the other circumferential direction until such time as the closure lug 78 of the grip element 12 moves past the closure recess 97 of the closure element 13, and the grip element 12 can be moved in the direction of the arrow S by the length of the closure lug 96. While this axial pressure in the direction of the arrow S on the grip element 12 is maintained, the closure element 13 can be moved in the direction of the opening motion, that is, counterclockwise, because of the relative rotational fixation, and thus the sealing cap 11 can be unscrewed.

[0030] In the axial motion of the grip element 12 in the direction of the arrow S by the length of the closure lug 78, the coupling insert 80, whose upper face end 84 rests on the inside of the grip element 12, is also moved axially in the direction of the arrow S, so that the first set of teeth 86 of the coupling insert 80 mesh with the third set of teeth 88 along the distance corresponding to the length of the closure lug 78. The result is an increase in the rotational fixation between the grip element 12 and the closure element 13. The first through third sets of teeth 86-88 are provided on the outside and inside circumferences with an axially oriented and circumferentially acting set of teeth, not shown in detail here. In the exemplary embodiment, the face ends toward one another of the sets of teeth 86 and 88 are provided, similarly to the embodiment in FIG. 4, with oblique faces in the direction O of the opening motion, so that a rotational fixation is achieved here as well, when the grip element 12 is moved axially by the aforementioned distance and the pressure in the direction of the arrow S is maintained. 

1. A sealing cap (11) for openings of containers, particularly motor vehicle radiators, having an outer cap part (10), which has a closure element (13) that can be connected to a container pipe and a grip element (12) that is retained rotatably relative to it; having a rotation preventer, which is provided with a coupling insert (80) that is axially engageable with and disengageable from the closure element (13) and is held in a manner fixed against relative rotation in the grip element (12), for releasable rotationally fixed connection of the closure element and grip element; and having a valve assembly (15), which has a valve body (17) that can be moved axially back and forth, for opening and closing flow connections between the container interior and the container exterior as a function of predetermined values of the internal container pressure, characterized by an axial mobility of the grip element (12), at least in its central area, relative to the closure element (13) whenever, upon simultaneous rotation of the grip element (13), with the coupling insert (80) disengaged, an axially engaging and radially acting rotationally fixed connection (95) is made possible on a circumferential region.
 2. The sealing cap of claim 1, characterized in that the grip element (12) has an inward-pointing axial annular attachment (76), which on a circumferential region has a lug (78) protruding from the face end, and that the closure element (13), on a circumferential region of a radial ring, has an axial indentation (97), which can be engaged by the lug (78).
 3. The sealing cap of claim 2, characterized in that the closure lug (78) and the axial closure recess (97) have oblique faces (79, 99) contacting one another in the direction of the opening motion.
 4. The sealing cap of at least one of claims 1-3, characterized in that the grip element (12) is kept spaced apart from the closure element (13) by an axially acting compression spring (73), and the grip element (12) is axially held on the pressure element (13) in the direction of action of the compression spring (73).
 5. The sealing cap of at least one of one of the foregoing claims, characterized in that an engagement motion of the disengaged coupling insert (80) is associated with the axial motion of the grip element (12) relative to the closure element (13).
 6. The sealing cap of claim 5, characterized in that the disengaged coupling insert (80) rests on a stationary stop (28) radially inside the rotationally fixed connection.
 7. The sealing cap of claim 5 or 6, characterized in that the coupling insert (80) is engageable only over an axial partial region.
 8. The sealing cap of at least one of claims 5-7, characterized in that the elements of the coupling insert that axially engage the inside of one another or engage side by side in the engagement motion of the coupling insert (80) are provided, on their ends oriented toward one another, with oblique faces acting in the direction of the opening motion.
 9. The sealing cap of at least one of one of the foregoing claims, characterized in that the axial disengagement and engagement motion of the coupling insert (80) is derived from the pressure-dependent axial motion of the valve body (17) of the valve assembly (15).
 10. The sealing cap of claim 9, characterized in that the coupling insert (80) is seated on the valve body (17).
 11. The sealing cap of at least one of one of the foregoing claims, characterized in that the coupling insert (80) on its outer circumference and the closure element (13) on its inner circumference are provided with an axially extending set of teeth (86, 88, respectively).
 12. The sealing cap of at least one of one of the foregoing claims, characterized in that the coupling element (80) is subjected to a compression spring (81), which is braced on the inside of the grip element (12).
 13. The sealing cap of claim 12, characterized in that the compression spring (81) is disposed radially inside the coupling element (82) of the coupling insert (80) and the closure element (13). 